Short wave tube



Feb. 11, 1936.

I B. SALZBERG' SHORT WAVE TUBE Filed June 23, 1954 BERNARD SALZBERG BY vD trodes and leads form an electrical system which Patented Feb. 11,1936 PATENT OFFICE SHORT WAVE TUBE Bernard Salzberg, New York, N. Y.,assignor to Radio Corporation of America, a corporation of DelawareApplication June 23, 1934, Serial No. 732.028

7 Claims.

My invention relates to electron discharge devices. more particularly toelectron discharge devices for use at ultra high frequencies and to themethod of making the same.

The maximum frequency at which the conventional tube will operate islimited principally by inter-electrode and inter-lead capacity and bythe inductance of the leads to the electrodes, because the inductanceand capacity of the elecdetermines the upper limit of frequency at whichthe tube will operate. While the inter-electrode capacity may bedecreased and thus the upper frequency limit at which a tube willoperate increased by making electrodes small, making them short. andbringing out leads at different points of the bulb, such a tube isdiflicult and expensive to make, because of special constructions andmethods required for assembling such tubes.

An object of my invention is to provide an electron discharge devicewhich may be made commercially even in very small sizes and in which theinter-lead capacity and the inductance of the leads are considerablyless than the conventional type. I

Another object of my invention is to provide an electron discharge tubein which the overall dimensions and inter-electrode spacing are muchless than is feasible in tubes constructed in the usual way.

A further object of my invention is to provide a simple and novel methodfor facilitating the assembly particularly of very small tubes intendedfor ultra high frequency use.

The novel features which I believe to be characteristic of my inventionare set forth with particularity in the appended claims, but theinvention itself will best be understood by reference to the followingdescription taken in connection with the accompanying drawing in whichFigure 1 is a perspective view, with parts broken away,

of an electron discharge device embodying my invention; Figure 2 is aperspective exploded view illustrating the method of assembling anelectron discharge device in accordance with my invention; Figures 3, 4and 5 are views showing modiflcations of details of construction of theelectron discharge device shown in Figure 1.

Referring to Figure 1, the envelope ID of the tube encloses and supportsa unitary electrode mount assembly comprising an indirectly heatedcathode II with the usual heater, 9. grid l2, and an anode II, which maybe a box-like structure made from sheet metal. The anode l3 has at eachend extensions II which form shoulders for supporting electrode spacersl5 and it of insulation, such as mica and preferably in the form ofplates or discs transverse to the longitudinal axis of the tube. Theextensions M are bent over against the mica plate members and may lie inslots in the edges of the plate members as shown to rigidly secure thespacers to the anode so as to provide a rigid unitary electrodeassembly.

In accordance with my invention radially positioned stiff conductors l'lwhich serve as leadin and mount support wires extend thru an exteriorannular press IS in the wall of the bulb l0 and have secured to theirinner ends, preferably by welding, conductors i9 having one end threadedthru apertures 20 in the insulating disc or plate member I5 to securethe conductors II to the plate member as best shown in Figure 4 and theother end electrically connected to one of the electrodes mountedbetween the plates l5 and It. The outer ends of conductors ll serve astube contacts to be received in a properly designed socket. Thisconstruction eliminates the need of the usual reentrant stem press andmaterially reduces the overall dimensions of the tube. It will beobserved that the grid and anode lead-ins are positioned on the oppositeside of the envelope from the heater and cathode leads to reduceinter-lead capacity and inductance. A

getter tab 2| is preferably fastened to an extenslon ll of the anode atthe opposite end of the mount from the lead-in conductors. U

A modification of the lead-in construction is shown in Figure 3. Herethe conductor I9 is first threaded thru and secured at one end to theinsulating mica spacer or plate member l5 near its periphery in anysuitable manner, for example as indicated at 22, and electricallyconnected at its other ends to an electrode. The lead-in conductors IIare then secured and electrically conthe advantage of providing a largesurface area 5- and of facilitating sealing. In this modification thelead-in conductor 25 is in the formof a flat strip welded at its innerend to the electrode conductor IS with its flat side in contact with themica disc spacer l5 and extends thru the annular press in a planeparallel to the spacer. 0n the exterior of the envelope the lead istwisted thru a 90 angle as shown at 26 to provide a knife blade contactwhich can be received by appropriate clip type socket contacts.

While various methods mav be used for assembling a tube-of the typedescribed inaccordance with my invention fuse the novel method illus-,,trated in Figure 2. After the electrodes have been assembled between theinsulating mica discs l5 and IE to provide a unitary mount structure,the combined lead-ins and tube contacts I! are secured to the mica discspacer l5. and connected to the electrodes by means of conductors I 9.The outer ends of conductors H are secured to a spacer ring 30 whichacts as a mount jig, or the leads may be first connected to the ring andthen secured to the insulating plate member i5. This assembly is thenpositioned so that the mount extends downwardly within the cup shapedportion 3| of the envelope l0 provided with an annular lip 32, thelead-in conductors resting on the lip. A second cup shaped portion 33 ofthe envelope l3 provided with the lip 34 is pos'tioned over the leads sothat the lips 32 and register with each other. Fires are then played onthe lips until the glass flows around the leads to seal the lips. Thelips may then be pressed together in a die, for example, to provide theoutwardly extending annular seal or press was shown in Figure 1, thruwhich the leads l'l extend. The ring 33 is then cut from the leads bysevering the leads, preferably in a single operation, a predetermineddistance from the edged the press. The tube is then thru the exhausttubing 35 after which it is tipped oil. This method of constructionpermits easy handling of the mount without injury during assembly andpromotes speed in the asembly operation while decreasing shrinkage inthe finished tubes.

A tube constructed in accordance with the above description may beeasily made of very small dimensions, is sturdy and reduces interleadcapacity and inductance to a very small value.

While I have indicated the preferred embodiments of my invention ofwhich I am now aware and have also indicated only one specificapplication for which my invention may be employed, it will be apparentthat my invention is by no 'means'limited to the exact forms illustratedor the use indicated, but that many variations may bemadeintheparticularstructureusedandthe p pose for which it is employed withoutdepartingfromthescweofmyinventionasset forth in the appended claims.

What I claim as new is- 1. An electron discharge device including anenvelope, a unitary electrode mount assembly positioned within theenvelope and comprising a pair of insulating plate members andelectrodes pmitioned between and secured to said members, radiallypositioned stifl' lead-in conductors extending thru the wall of saidenvelope, means on the inner ends of the radially positioned conductorssecuring the conductors to one of said insulating members for supportingthe mount within the envelope and for electrically connecting theconductors to the electrodes positioned, between the insulating platemembers.

2. An electron discharge device including a glass envelope, a unitaryelectrode mount assembly within saidenvelope comprising an insulatingplate member and electrodes seemed to said plate member, stlfl lead-inconductors sealed connected to an electrode in said electrodemountassemblywhereby said mount'is supported within said tube by saidradially positioned lead-in conductors.

. electron discharge device ,including an envelope, a unitary electrodemount assembly po- .sitioned within said. envelope and comprising atransverse insulating plate member and spinrality of electrodes securedto said'plate member, fiat conductors extending radially thru the wallof the envelope with a flat side in contact with the insulating platemember, the outer end of each of said fiat conductors being twisted thruwith respect to the inner end to provide a knifeblade contact,conductors secured inter,- mediate their ends to the inner ends of saidfiat conductors and having one end extending thru and secured to theinsulating plate member and the other end'electrically connected to oneof the electrodes in the mount to provide a support for the mount and alead-in for the electrodes.

4. 1m electron discharge device comprising an envelope, an electrodemount assembly positioned in the envelope, fiat lead-in conductorsextending radially thru the wall or, the envelope with a fiat side lyingin a plane transverse to the 1021- I gitudinal axis of said electrondischarge device, the outer ends of said fiat lead-in conductors beingtwisted thru 90 to provide knife blade contacts and means for connectingthe inner ends of said lead-in conductors to said mount assembly.

5. The method of assembling an electron discharge deviue comprisingassembling the electrodes into a unitary mount structure having aninsulating member at one end, securing radially positioned lead-inconductors at their inner ends to said insulating member andelectrically connecting each conductor to one of the electrodes in themount assembly, and connecting the outer ends of said lead-in conductorsto a ring positioning the mount structure within a cup-shaped memberprovided with a glass lip, positioning a second cup-shaped memberprovided with aglass lip over the open end of said first cup-shapedmember with the lips in registry with each other. applying heat to thelips of said cup-shaped members to provide an annular seal thru whichthe radially positioned lead-in conductors extend, and severing the ringfrom said lead-in conductor's adjacent their outer ends exhausting theelectron discharge device thru an exhaust tube extending outwardly thrua closed end of one of the cup-shaped members and tipping 011' saidexhaust tube.

6. The method of assembling an electron discharge device comprisingassembling the elec 'trode into a unitary mount structure having anmember with the lips in registry with each other, i

and sealing the lips of said cup-shaped members to provide an annularseal thru which the leadin conductors extend and severing the ring fromsaid lead-in conductors adjacent their ends.

7. An electron discharge device including an envelope, a unitaryelectrode mount assembly positioned within said envelope and comprisinga pair of insulating plate members and electrodes positioned between andsecured to said plate members, stiif lead-in conductors sealed into andextending thru the wall of the envelope toward said unitary electrodemount assembly with the inner ends of the lead-in conductors positionedaround one of said insulating plate members,

each of said lead-in conductors having a second conductor securedintermediate its ends to the inner end of the stifi lead-in conductor,said second conductors having one end secured to said one of saidinsulating plate members and its other end electrically connected to anelectrode in said electrode mount assembly, whereby said mount assemblyis supported within said envelope by said stifl' lead-in conductors, theouter ends 01' said stiff lead-in conductors being external contacts tomake connections to a socket.

BERNARD SAIZBERG.

